With respect to cars, you might want to at least have them kick in a good percentage. I knew innumerable kids in high school and early college who were given new, expensive, autos and subsequently trashed them, some repeatedly. I worked like hell to save for a car, and was, at the time, majorly surprised when the Parents kicked in 1/3 of the $2600 on my birthday. I ended up having that car for 7 years, and along the way learned proper "care and feeding" to the point that I had 6 others by the time I graduated college.
If you want to teach your child a very important lesson, you buy a 10 year old Ford Taurus with about 100k miles for about $3000. Let them drive it, them paying for maintenance, gas and insurance, for 4 years, then sell it for about $2000.
Cost of ownership - aboout $250 per year. When they start shopping for their own car, $21/month may just register in their newly educated brains as they look at new cars going leasing for $400/month.
My parents got me a new car when I was 16. I took great care of that car.
My parents helped my older brother buy a used car. He paid for most of it, and they paid for some of it. He totalled it. In fact, he totalled something like 3 cars.
Like I said earlier, it just depends on the kid. I was always a very hard worker (good grades, didn't get into trouble, etc). My brother was always on the edge. Barely finished college, got into more trouble than me, etc.
Both of us actually turned out okay.